It’s a wonderful time to be a health and fitness professional working with prenatal clients. Not only is it O.K. for pregnant women to exercise during a healthy pregnancy, it’s strongly recommended. In fact, a considerable body of research confirms substantial benefits for both mom and baby when fitness is added to a woman’s healthy prenatal journey. But what about when conditions are less than ideal, like in the sizzling summer months, when both temps and humidity are soaring? Should a pregnant woman continue exercising in a hot environment?

Safety First

The answer is, of course, a qualified yes—as long as specific precautions are taken and the safety and well-being of both mom and baby are the first priority. Read on for a brief review of exercise recommendations for pregnant women, along with precautions and tips for exercising in heat and a sample workout that can be used with individual clients or in a class setting.

Exercise and Pregnancy 101

Before we discuss tips for exercising while pregnant in the heat, here is a brief review of specific considerations, including exercise intensity and heat dissipation, and established exercise guidelines for pregnant women.

It is important to realize that the prenatal body, in a healthy pregnancy, is a state of health. In the past, recommendations have run the gamut from “keep going no matter what” to “don’t walk upstairs or carry anything heavier than 10 pounds.” Fortunately, times have changed and it is now well established that exercise during pregnancy is hugely beneficial. Here’s what the American College of Obstetricians and Gynecologists (ACOG) recommends:

“If you are healthy and your pregnancy is normal, it is safe to continue or start most types of exercise, but you may need to make a few changes.”

The changes, they state, are primarily related to intensity and the types of activities a woman should and should not do (avoiding sports with high risks of falling or abdominal trauma, for example).

Intensity: The Centers for Disease Control and Prevention recommends that pregnant women get at least 150 minutes of moderate-intensity aerobic activity every week. Moderate intensity means you are moving enough to raise your heart rate and start sweating. You still can talk normally, but you cannot sing. ACOG also addresses women who were already active prior to becoming pregnant: “If you were very active before pregnancy, you can keep doing the same workouts with your healthcare professional’s approval.”

Heat Dissipation: During pregnancy, a woman’s body is actually better able to dissipate heat than it was before she was pregnant. In fact, according to one of the leading researchers in prenatal fitness, Dr. James F. Clapp, “Both pregnancy (a growth process) and regular exercise (mechanical work) generate extra heat that the mother’s body must either store of eliminate. A woman’s body responds to both thermal stresses by improving its capacity to eliminate the extra heat generated.”

The human body dissipates heat through both sweat and breath. During pregnancy, a woman’s body begins to sweat at a cooler temperature than before she became pregnant. This is a feto-protective mechanism in place to protect the baby. In addition, the prenatal body experiences an increase in oxygen exchange by about 40 to 50%. That means, says Dr. Clapp, that “heat loss through breathing increases 40 to 50 percent as well.”

Safety First

As we head into the summer months, there are certain precautions to keep in mind to ensure your pregnant clients are comfortable and are exercising in a way that is safe for both mom and baby. Even though a woman’s body is better able to dissipate heat than before she got pregnant, you still need to take specific precautions when designing programs for your pregnant clients. Specifically, ACOG recommends: “During exercise, pregnant women should stay well-hydrated, wear loose-fitting clothing, and avoid high heat and humidity to protect against heat stress, particularly during the first trimester. Although exposure to heat from sources like hot tubs, saunas or fever has been associated with an increased risk of neural tube defects, exercise would not be expected to increase core body temperature into the range of concern.”

 Here are some additional tips to offer your pregnant clients to help ensure that they exercise safely and comfortably during the warmer months:

• Drink water. Dehydration can happen fast, which can result in feeling faint or dizzy. It can also add to increased fatigue. Keep drinking water throughout the day and during exercise to stay hydrated.
• Consider the time of day. When exercising outdoors, avoid working out in the hotter times of the day (11 am to 3 pm). Exercising in the early morning or evening, when temps are usually lower, is generally safer. 
• Be a “shade chaser.” If exercising outside, look for the shaded areas of your location and try to stay in those sections as much as possible.
• Cool off frequently. Bring a wet towel or spray bottle to cool off throughout the workout. Focus on the head and neck for a faster cool-down.
• Wear breathable clothing. Clothing should be light and allow for the release of body heat during exercise. 
• Exercising indoors is always an option. If an indoor venue is an option for your pregnant client’s workouts, this could be a great solution to help regulate temperature, especially for days when the heat and/or humidity are especially uncomfortable.

Sample Prenatal Workout

Whether performed indoors or outside in the shade, this is a great circuit routine using weights or resistance bands to use with your pregnant clients. Insert a brief rest between each minute and urge clients to take sips of water throughout the workout.

Start with a 10-minute dynamic warm-up, which could include a walk or easy jog.

Perform each of the following exercises for one minute, followed by a brief rest before moving on to the next exercise.

• Hamstring curls (walking or running)
• Hay baler (squat with a diagonal lift)
• Curtsy lunge with a lateral raise
• Jumping jacks (high- or low-impact)
• Plié squat with biceps curl
• Alternating forward lunges with triceps kickbacks
• Speedskaters (stepping or jumping side to side in a low squat)

Repeat two to three times, based on energy level and time available. Finish with a cool-down and stretching exercises.

Conclusion

Continuing to exercise throughout pregnancy is the best way for a woman to help increase both her circulation and her energy levels as she moves from trimester to trimester. It also aids in increased mental and physical strength for labor and delivery. Finally, prenatal fitness prepares a woman’s body for her new role as MOM (a pretty physical job!). Helping your clients understand the considerations and modifications around exercising during the summer months is essential to ensuring she stays safe and continues on her fitness journey without being sidelined by the heat.